Well, I've been away from this thread for awhile due to moving, but I thought I'd provide an update. First, my new 240 is working perfectly (my original had a problem with a skitish volume control that was confirmed by iriver as being defective). I have over 400 hours on it and it now sounds like my old one ... utterly fantastic. Burn-in is critical for the 240 to sound its best. My new cable from DHC came in which allows me to connect my LCD-XCs to the balanced output. I put another 100 hours on my setup before I did any critical listening.
What I am noticing using the balanced output is a more organic sounding bass. What I mean by this is the bass is no longer one note in variety, rather, a breathing, more detailed bass. There are better micro/macro dynamics now which make the low end more involving, even startling at times. Additionally, the soundstage has improved in terms of front to back depth, not as much laterally. Please remember I have closed back headphones, so the lateral soundstage is not going to be as wide as an open-eared design, at least in my experience. This may account for my perception about improvements in soundstage width.
I'm still trying to pin down the differences in other areas since I haven't used my setup for 3 weeks due to my moving and to all the burn-in time. I'll report back more as I get a better handle on the midrange and upper frequencies, but my quick assessment is the new cable/balanced out change has elevated the sound on my XCs about 15%—not a bad return on my $250 investment.
All in all, I'm even more happy—thrilled, in fact—with my setup.
Incidentally, I just heard from Ted at teds headfood that the new cases for the 240 are going to retail for $80.